Shell Programming and Scripting

Type of arg 1 to each must be hash (not string) at ./script.pl line 10, near ""$hash" ) "

#!/usr/bin/perl -w

 my $svhref;
 my $serial = "0629AN1200";

sub PrintHash($)
{
my $hash = shift;

 while ( my ( $key, $value ) = each "$hash" ) {
        print $key, " ->\n";
        while ( my ( $key, $value ) = each %$value ) {
             print "\t", $key, " -> ", $value, "\n";
        }
 }
   print "\n";
}


open(IN, "$serial.txt") or die "can't open $serial.txt $!\n";
  while (<IN>)
  {
     chomp();  # remove line feed
     my ($nic_name, $nic_speed, $nic_duplex, $nic_ip)  = split(/\|/);
     $svhref->{ $nic_name } = {
                nic_speed => $nic_speed,
                nic_duplex => $nic_duplex,
                nic_ip => $nic_ip,
            };
  }  
  close(IN);
  
PrintHash('%$svhref');

while ( my ( $key, $value ) = each "$hash" ) {

 while ( my ( $key, $value ) = each %$hash ) {

PrintHash('%$svhref');

PrintHash($svhref);

use Data::Dumper;
print Dumper(\%svhref);